Shape memory alloy staple

Abstract

A fusionless method of correcting spinal deformities in growing adolescents is disclosed utilizing a shape memory alloy staple. Various embodiments of the shape memory alloy staple include features such as barbs on the inner and outer surfaces of the prongs in the shape memory alloy staple as well as the use of notches on the crossbar or cross plate connecting the prongs to the shape memory alloy staple. In some embodiments, the shape memory alloy staple has an aperture defined through the cross plate for receiving a bone screw or other bone anchor which in turn allows the interconnection of a longitudinal member.

What is claimed:  
     
       1. A spinal staple, comprising: 
       a cross member defining an opening extending therethrough;  
       a first prong extending from a first end portion of said cross member; and  
       a second prong extending from a second end portion of said cross member; and  
       wherein the staple is at least partially formed of a shape-memory material having a memorized state and a deformed state, said opening having an initial cross section when in said deformed state and a different cross section when in said memorized state.  
     
     
       2. The spinal staple of  claim 1 , wherein said initial cross section is larger than said different cross section. 
     
     
       3. The spinal staple of  claim 1 , wherein said opening is generally circular. 
     
     
       4. The spinal staple of  claim 1 , wherein said initial cross section is sized to receive a portion of a bone anchor; and 
       wherein said different cross section is sized to capture said portion of the bone anchor.  
     
     
       5. The spinal staple of  claim 1 , wherein said first and second prongs are disposed closer to one another in said memorized state than in said deformed state. 
     
     
       6. The spinal staple of  claim 1 , wherein a pair of said first prongs extends from said first end portion of said cross member; and 
       wherein a pair of said second prongs extends from said second end portion of said cross member.  
     
     
       7. A spinal staple, comprising: 
       a cross member;  
       a first pair of prongs extending from a first end portion of said cross member;  
       a second pair of prongs extending from a second end portion of said cross member; and  
       wherein the staple is at least partially formed of a shape-memory material having a deformed state and a memorized state, said first and second pairs of prongs being disposed closer to one another in said memorized state than in said deformed state.  
     
     
       8. The spinal staple of  claim 7 , said cross member includes an opening extending therethrough, said opening having an initial cross section when in said deformed state and a different cross section when in said memorized state. 
     
     
       9. The spinal staple of  claim 8 , wherein said initial cross section is sized to receive a portion of a bone anchor; and 
       wherein said different cross section is sized to capture said portion of the bone anchor.  
     
     
       10. The spinal staple of  claim 7 , wherein each prong of said first and second pairs of prongs includes a distal portion, said distal portions of said first and second pairs of prongs being disposed closer to one another in said memorized state than in said deformed state. 
     
     
       11. The spinal staple of  claim 7 , wherein each prong of said first and second pairs of prongs includes a distal portion defining a pointed tip to aid in insertion of said first and second pairs of prongs into bone. 
     
     
       12. The spinal staple of  claim 7 , wherein said first and second pairs of prongs are substantially parallel in said deformed state. 
     
     
       13. The spinal staple of  claim 7 , wherein said first and second pairs of prongs are angled toward one another when transformed toward said memorized state. 
     
     
       14. The spinal staple of  claim 7 , wherein said cross member includes an inwardly facing concave surface. 
     
     
       15. The spinal staple of  claim 7 , wherein said first pair of prongs are interconnected by a first arched portion, and wherein said second pair of prongs are interconnected by a second arched portion. 
     
     
       16. The spinal staple of  claim 7 , wherein each prong of said first and second pairs of prongs is curved. 
     
     
       17. The spinal staple of  claim 16 , wherein each prong of said first and second pairs of prongs includes an inwardly facing concave surface. 
     
     
       18. The spinal staple of  claim 16 , wherein each prong of said first and second pairs of prongs includes an inwardly facing convex surface. 
     
     
       19. The spinal staple of  claim 7 , wherein transformation from said deformed state toward said memorized state causes a dynamic compression. 
     
     
       20. A spinal staple, comprising: 
       a cross member;  
       a first pair of prongs extending from a first end portion of said cross member;  
       a second pair of prongs extending from a second end portion of said cross member; and  
       wherein the staple is at least partially formed of a shape-memory material having a deformed state and a memorized state, said first and second pairs of prongs being disposed closer to one another in said memorized state than in said deformed state, wherein transformation from said deformed state toward said memorized state occurs without a corresponding change in temperature.  
     
     
       21. An apparatus for treatment of the spine, comprising: 
       at least two staples, each staple being at least partially formed of a shape-memory material having a deformed state and a memorized state, each staple comprising:  
       a cross member defining an opening extending therethrough;  
       a first prong extending from a first end portion of said cross member; and  
       a second prong extending from a second end portion of said cross member,  
       wherein said first and second prongs are disposed closer to one another in said memorized state than in said deformed state;  
       at least two bone anchors, a portion of each bone anchor extending through said opening in a corresponding one of said staples; and  
       a longitudinal element interconnecting said at least two bone anchors.  
     
     
       22. The apparatus of  claim 21 , wherein said opening has an initial cross section when in said deformed state and a different cross section when in said memorized state. 
     
     
       23. The apparatus of  claim 22 , wherein said initial cross section is sized to receive said portion of the bone anchor; and 
       wherein said different cross section is sized to capture said portion of the bone anchor.  
     
     
       24. The apparatus of  claim 21 , wherein a pair of said first prongs extends from said first end portion of said cross member; and 
       wherein a pair of said second prongs extends from said second end portion of said cross member.  
     
     
       25. The apparatus of  claim 21 , wherein said at least two bone anchors are capable of being engaged to respective ones of said vertebral bodies. 
     
     
       26. The apparatus of  claim 21 , wherein said at least two bone anchors are bone screws. 
     
     
       27. The apparatus of  claim 21 , wherein said longitudinal element is a spinal rod. 
     
     
       28. An apparatus for treatment of the spine, comprising: 
       an implant capable of being disposed between adjacent vertebral bodies; and  
       a staple at least partially formed of a shape-memory material having a deformed state and a memorized state, said staple comprising:  
       a cross member;  
       a first prong extending from a first end portion of said cross member and capable of being engaged to one of said vertebral bodies; and  
       a second prong extending from a second end portion of said cross member and capable of being engaged to another of said vertebral bodies; and  
       wherein said first and second prongs are disposed closer to one another in said memorized state than in said deformed state; and  
       wherein transformation from said deformed state toward said memorized state compresses said vertebral bodies against said implant.  
     
     
       29. The apparatus of  claim 28 , wherein said staple is capable of retaining said implant between said adjacent vertebral bodies. 
     
     
       30. The apparatus of  claim 29 , wherein said staple inhibits movement of said implant relative to said adjacent vertebral bodies. 
     
     
       31. The apparatus of  claim 28 , wherein said implant is a graft. 
     
     
       32. The apparatus of  claim 28 , wherein said implant is a fusion device. 
     
     
       33. The apparatus of  claim 28 , wherein a pair of said first prongs extends from said first end portion of said cross member; and 
       wherein a pair of said second prongs extends from said second end portion of said cross member.  
     
     
       34. The apparatus of  claim 28 , wherein said first and second prongs are substantially parallel in said deformed state and are angled toward one another in said memorized state.